intro to cassette recorder operation, maintenance, and repair

instructables

Intro to Cassette Recorder Operation, Maintenance, and Repair

by ke4mcl

As somebody who lived through the cassette tape era, to see it come around again is interesting and nostalgic. I see lotsof groups all over the web dedicated to tape and tape machines but still there's plenty of basic questions that gounanswered.

In this instructable I hope to take you from zero to hero when it comes to cassette deck terminology, machine operation,and basic maintenance and repair. Some of the things we discuss involve opening the machine and maybe evenoperating the machine with the cover o . You can get shocked if you're not careful. Use your judgement. On any machinethat plugs into a wall outlet you can have unguarded mains voltage exposed inside the cabinet. Please be careful andseek help from a trained person if you feel you're in over your head.Supplies:

What you'll need..

This all depends on what you want to accomplish but I assure you it's all basic stu . All tape machines require frequentcleaning if used often. For this you'll need Q-tips or similar and head cleaning uid. What's head cleaning uid? I'll explainthat in the head cleaning part of the instructable. Additionally, Windex or similar and isopropyl alcohol should be part ofyour toolkit.

For more involved stu like belt changes or lubing a motor for example you should have a set of good quality basic handtools (screwdrivers, small pliers, dental pick at minimum), light machine oil, and patience.

The last tool you'll need is a digital camera with good resolution. Nothing beats having pictures to refer back to as youwork on something. Your phone is ne for this.

Intro to Cassette Recorder Operation, Maintenance, and Repair:

http://www.instructables.com

http://www.instructables.com/Intro-to-Cassette-Recorder-Operation-Maintenance-a/

http://www.instructables.com/member/ke4mcl/

Step 1: Transport Controls, What Tells the Tape to Move

So our rst stop will be talking about the controls for the transport. The transport is the mechanism that physicallyhandles the movement of the tape. It's what winds the tape in one direction or the other and what engages the headsfor playback and recording. Transport controls can be roughly grouped into two categories, mechanical and electronic.

MechanicalMechanical controls actuate rods, levers, and gears and cause the mechanism to do what you requested. The mostcommon of these is the piano key style as seen in pics 1 and 2. Piano key controls are very common on decks from the60's up until the 80's. You push down on a lever that makes part of the internal mechanism move. Similar mechanisms,though not as exposed, were used in almost every "shoe box" (pic 1) style portable cassette recorder.

Pics 3-8 show some other types of transport controls found on portables. Instead of a lever you push down upon youhave a rocker mechanism or a button. Not pictured is the style found on the rst cassette recorder which is a lever thatmoves side to side. There were also some machines that used a knob you turned to do di erent functions. All are stillmechanical in operation. As long as you don't force the mechanism or try to get it to do two things at once, they are fairlyrobust and rarely require repair.

Pics 9-10 show examples of the controls to an electronically controlled electronically controlled transport. In these, you push a button that isactually a switch which causes a very basic computer system in the deck to actuate a solenoid that engages whateverfunction you requested. Keep in mind when I say basic computer, I mean the lowest Arduino can run marathons aroundit!


What's the bene t to the electronically controlled transport? It protects itself from users trying to cycle it too fast or jam itinto two modes at once. It also allows for some basic automation. Looking closely at pics 9-10 one deck has an "autospace" function and the other a "search" function. Auto Space automatically inserts a certain amount of blank space atthe end of a recording and then stops the deck. Search function is just that, it fast forwards looking for music, when it

nds it, it stops, rewinds a touch, then plays. These automations are possible with an electronically controlled transport.Remote control didn't become economically viable until electronically controlled transports came around.

On some decks you may see the term CUE/REVIEW. This allows you to listen to the audio as you are fast forwarding orrewinding. While it makes nding music on a tape easier, it does shorten the life of the heads (part that reads the tape) ifused extensively.

One nal type of transport control to mention that lies partially between mechanical and electronic, power assistedpower assistedmechanicalmechanical. There was an interim time where manufacturers wanted something di erent but didn't want to spend themoney on a still expensive fully electronic transport. They came up with a mechanical transport that uses the tape deck'smotor to fully engage a button for you. You still have a mechanical button but when you push it, the mechanism kicks inand greatly lessens the force necessary to activate the function. These decks while novel are very prone to jamming oncethe belt goes slack. The user hits a button, the mechanism kicks in, the belt starts to slip, and that's it... stuck deck. Easy to

x by opening the deck and turning mechanism by hand but many end up with ripped o doors from angry users tryingto extract their tapes.


Step 2: Transport Parts - Belts, Sensors, Motors and Other Bits

BeltsBelts.. The bane of the cassette enthusiasts world!

Why belts? Belts allow the transfer of force from the motor to the other parts of the mechanism. The electric motors usedin cassette decks don't run 100% smooth, They kind of micro-nudge along and this nudging must be smoothed out. Thesmoothing out is done by the elasticity of the belt which provides mechanical isolation and by a ywheel. With theexception of one esoteric Eumig brand deck, all cassette decks have ywheels.

In pic 1 you see the inside of a lowly GE shoe box recorder. It's basic operation isn't much di erent than that of a high endhome audio deck. You mash a button, it engages the mechanism, the motor turns on, things happen. This machine has asingle motor transport. One motor does it all. This setup is common to entry level machines. One motor can do it all butits not ideal as there's more variables to control AND keep the motor speed from uctuating.

In that pic you see a whitish plastic pulley on the left, that's the motor pulley. As you follow the belt around, it rides past alarge metal pulley, that's the ywheel which drives the capstan. What's a capstan? I'll explain that when we get into thepart of the deck the cassette goes into. Finally on the belt's route is a black plastic pulley. That one drives the hubs. Thehubs are what moves the tape along in FFWD or REW. This setup is very common on portables and low end home decks.

Pics 2-3 show the transport of a Harmon Kardon home deck. Not a cheap deck but they used a single motor to doeverything, obviously done to please the accountants. The deck still achieves very good specs by using a very heavy

ywheel and large motor.Intro to Cassette Recorder Operation, Maintenance, and Repair:

In pic 2, right below the number 12 on the motormotor, you see a small hole. This is a speed adjustment port. A small atheador philips (depending on motor) inserted there can be used to adjust speed. Not all cassette deck motors have this but agreat many do. The screwdriver should have its shaft insulated as some motors have the part in the motor you adjustinside at one electrical potential and the case at another. This is not a x for a slack belt. This is not a x for a draggingtransport that needs to be cleaned and lubed. This is intended to be used with a speed adjustment tape and a frequencycounter. You play a tape that has a tone on it that was recorded on calibrated equipment. The output of the machine youare working on is connected to a frequency counter and the motor speed is adjusted until the correct frequency showson the counter.

On older top loaders, it's not uncommon to nd a large AC motor instead of a small DC can motor. Decks with those largeAC motors don't have speed adjustments. If the deck is playing slow, the belt is slipping or the mechanism is draggingand needs to be cleaned and lubed.

Higher end decks can have multiple motors dedicated to speci c functions.

In pic 4 you see a belt going to a wheel shaped part. This is the auto stop sensorauto stop sensor. The auto stopauto stop mechanism does justwhat the name implies, it automatically stops the machine at the end of the tape. This can be only in play mode as foundin very old or basic decks or can be in any mode in which there is tape movement. This is done to lessen wear on themachine when it's left unattended. Auto stop can be achieved two ways, monitor tape movement or a physical leveragainst the tape that trips when there's too much tension.

The mechanical system uses a plastic nger that reaches into the cassette right next to where the heads go in to read thetape. The nger rides on the tape. When the tape reaches it's end, the mechanism pulls it tight, this puts tension on thelever causing it to trip the auto stop.

The electronic system uses a hall e ect sensor or an optical sensor. If the tape is moving, the sensor wheel is turning, thecircuit that monitors it says all is well. Once you hit the end of the tape, the counter stops moving, the sensor wheel quitsturning, the auto stop sensor detects no pulses and it stops the machine.

It's not uncommon to nd the electronic sensor system tied to the tape counter mechanism as is done in pic 4. It doesn'thave to be implemented this way but you will see this. The belt that drives the counter is important but not speed critical.In a bind? a rubber band will work for a while.

On either type of auto stop setup, it may be possible to engage play without a tape. This is not a aw. This makes it easierto clean the capstan and pinch roller. Remember the auto stop is really for detecting the tape is at its end and mechanismis binding up.

Some higher end decks will use sensorssensors to detect how many times the hubs have turned to try to give you an actualtime left on a tapetime left on a tape versus just a counter that has no relation to time. This is built into the transport and not typicallyaccessed for basic repairs or maintenance.

Not all cassette decks have auto stop. Some of the very early machines didn't have it and it took a while for the lowbudget machines to implement it. How do you know if your machine has it? On many machines it will clearly say itsomewhere near the transport controls. Another way to check is put a tape in that's already rewound and hit the REWbutton. It should try to rewind and then give up and stop. On some early machines you had auto stop only on play mode.This means when the tape hit the end, the machine would stop but only when in play mode. If it was in FFWD or REW themotor would keep running and a felt clutch under the hub would just slip. Best bet is don't leave the machine runningunattended until you verify that your machine has auto stop and it works.

"My deck says auto reverse. What does that mean?""My deck says auto reverse. What does that mean?"

Auto reverse means the machine is capable of playing both sides of a tape without you having to ip it over. There weresome really interesting ways of doing this were some machines actually ipped the tape over. These machines are cool towatch but rare nds. The great majority of auto reverse decks simply change the direction of play and ip the headsaround on a rotating mechanism inside the deck. This is by far the most common way its handled. On some home decks,


most portables, and car stereos the way they handle playing both sides is the head (part that reads the tape) is setup toread all 4 tracks at once so it's just a matter of changing tape direction and electronically selecting what tracks to listen to.A standard stereo cassette has 4 tracks, 2 per side.


Step 3: How to Tell If a Belt Is Bad & Replacement

How do I know a belt is bad? On a working machine, warbly play, random stopping, incomplete FFWD or REW operationscan indicate bad belts. On a non working machine that powers on and things all look normal but nothing happens whenbuttons are pushed, it can be a bad belt.

"Can I replace the belts myself?""Can I replace the belts myself?"

Maybe. How good are you with mechanisms and how intricate is the machine you are working on? The GE in the pictureis a cakewalk. A few screws and your in. Some other machines may require extensive disassembly and the skills of awatchmaker to get everything back together. That's beyond the scope of this instructable but there's only one way tolearn and it's by doing. Please keep in mind that even if broken, some cassette decks can be worth hundreds, a few pastthe thousand dollar mark. Research what you got before using it as a Guinea pig to learn on.

"Where do you buy belts?""Where do you buy belts?"

There are a few sources online that sell tape recorder belt kits. The better kits will include some instructions and have allthe belts you need in the correct sizes. This is the safest way to get the job done without error but also the mostexpensive. There are vendors selling belt lots. This can save you a bunch of coin but now you need to be able to properlysize the replacement belt (comes with experience) and the quality of those belt lots varies drastically.

"Can I use rubber bands?""Can I use rubber bands?"


Yes, and the machine will perform horribly. Rubber bands are too springy. Proper tape machine belts have very little givewhen it comes to being stretched. Give translates into warbly audio due to inconsistent speed. In a bind rubber bandscan be used for non critical things like the counter but they don't last very long.

THIS IS GONNA GET DIRTY... you've been warned!THIS IS GONNA GET DIRTY... you've been warned!

Old tape deck belts can fail in three ways, stretchstretch, meltmelt, or dry rotdry rot.

Melt Melt and dry rotdry rot are easy to check for. Open the deck up and look at the belt that goes around the ywheel and aroundthe motor. Is the belt present or did it turn into a mess of black goo? DO NOT TOUCH DO NOT TOUCH the black goo. It gets on everythingand ruins clothes. It's like tar. Magic melting belts are to be expected in old cassette decks. If the belt melted long agoand wasn't disturbed, you may actually luck out and it's gone into a dried out hardened state which is much easier toclean up. Either way, this can be cleaned up and xed. Got some on you? Ammonia based window cleaners dissolve itand make cleanup easier.

What if the belt is present, not melted, and looks okay? Here's how you check for stretchstretch. Let's go back to the pic of theold GE shoebox recorder for a second. The big metal wheel is the ywheel that's attached to the capstan. The main belt,and possibly the only belt on some machines, runs around that ywheel and onto the motor. With the deck opened up,power it up and hit play. If it won't stay in play, try putting a cassette in you don't care if you loose just to keep the autostop mechanism happy. A good belt will have grip on the motor pulley. To determine if the belt is still good simply putthe machine into play mode and with your nger, stop the ywheel from turning. When the ywheel stops, the motorshould stall. If the motor does not come to a complete stop, you have a stretched or worn belt. Don't do this for morethan a second or so, it's hard on the motor.

Tape decks can have more than one belt or a combination of belts, gears, and tiny rubber tires to handle the shu ing ofthe tape. Always replace all the belts when servicing a deck due to a bad belt. Remember, they are all the same age so allare degrading together.

"I've got black goo all over the inside the mechanism, now what?""I've got black goo all over the inside the mechanism, now what?"

Q-tips and Windex or similar ammonia based glass cleaner to the rescue. Pour some Windex into a disposable shot glassor something similar sized, dip the Q-tip in Windex, start cleaning. Windex dissolves the melted belt goo. You will gothrough MANY Q-tips. Anything that goo gets on, it sticks to. It's vile stu . Don't stop till it's all cleaned up. Make sure theV groove in the pulleys is COMPLETELY free of black goo. Leaving any in there will accelerate the failure of the new beltand drag down the mechanism speed.

If the machine uses small rubber ringed wheels for part of it's operation, clean those as well. This can be challenging assome will be well hidden but with patience you can clean, move it a little, clean, etc. clean both the rubber tire surfaceand the surface it rides on.


Step 4: Let's Look at the Parts Inside the Tape Well - Hubs, Pinch Roller and Capstan

In pic 1-4 you see the inside of the tape welltape well on 3 di erent cassette decks and a microcassette deck (note similarities).The tape well is where you insert the cassette into the machine. This can be via a slot in the door were you load the tapeand it aligns it for you as you shut the door or it can be like what's used in some portables where you lay the tape into themechanism. Regardless of who made the machine, The all have the parts we are going to talk about.

Let's concentrate on pic 1. In the center you see two black nubs with ridges. Those are the hubshubs. They drive the tape backand forth for FFWD and REW along with taking up the slack as you play a tape. Got a machine that "eats" tapes? Oftentimes it's the take up hub slipping and not spooling the played tape up fast enough to keep it from being knotted up inthe machine. You can catch this by watching it as it plays. What causes that? Slipping belts or glazed idler wheels is acommon fault. A binding tape can also cause that. Really low end machines that don't have rewind will have only 1 huband a peg where the other hub would be.

On the rear left of pic 1 you see a vertical metal shaft with a rubber tire behind it. The is the capstancapstan and the pinch rollerpinch roller.These two are responsible for maintaining consistent play back speed. When you insert a tape into a cassette deck, theshell is designed so the tape media threads between the capstan (vertical metal shaft) and the pinch roller (rubber tire).When you hit play, the mechanism mashes the pinch roller against the capstan shaft, pinching the tape in a tight grip,thus being able to control it's speed as it plays. Remember that ywheel on the backside of the mechanism wediscussed? That ywheel is attached to the capstan shaft.


What can go wrong here? The biggest fail here is lack of maintenance. Not cleaning old residue from countless hours oftape builds up. Tapes shed oxide. Older tapes and low quality tapes tend to shed the most. They leave a rust lookingresidue on the pinch roller, capstan, and the heads (we'll talk more about those soon). As the residue builds up, it doesn'thappen evenly. At rst it just a ects the sound, making good tapes sound dull. As the residue gets real bad, it can actuallycause the machine to eat tapes by forcing the tape out of alignment. Pic 2 shows what a well used but clean roller shouldlook like. Aside from possible physical damage caused by an angered user, these parts are fairly robust. The rollers onsome very old machines can harden causing problems. The only x is to nd a donor machine with a similar sized rollerand replace it. Maintenance wise cleaning these parts is all that's usually needed and a tiny amount of oil applied with atoothpick where the capstan shaft enters the mechanism. This is to oil that bearing. Clean o excess with a Q-tip.

pic 3 is the well of an autoreverse machine. Note it has 2 capstans and 2 rollers. This is because the pinch roller that isengaged is always after the head. When the tape direction changes, the roller on one side disengages and the roller ofthe other side engages. The capstans on autoreverse machines turn opposite directions. The motor doesn't reverse, themechanism handles direction change.

The exception to this rule (isn't there always?). High quality machines may be labeled as being "closed loop". This meansit has two capstans and two rollers that both engage simultaneously, turning the same direction, to keep precise tensionon the tape as it goes across the heads. No matter, clean them BOTH.

So what do you clean these with? The CORRECT answer is Q-tips or similar, head cleaning liquid on the capstan shaft, andpinch roller cleaner on the roller. What have I been using since the 80's and never had a failure? Q-tips and rubbingalcohol. I can hear the cries of blasphemy as I type... Never had a failure and always been able to produce top notch tapesfrom my decks. Some folks use 80-90% isopropyl alcohol. I've had zero issues with regular drug store rubbing alcohol onboth roller and heads. I own over 100 machines and welcome anyone to come do forensics on them. The concern withrubbing alcohol is it can leave a residue. There's also been concern of drying out the rollers. Ok, once your down cleaning,give everything a once over with a clean dry Q-tip and rock on. I have yet to have issues on everything from Naks, toSony's.

An added little bonus, literally. The last picture is the tape well inside a microcassette deck. Notice the same stu , placed alittle di erently. It does the same, it's cleaned the same.


Step 5: Let's Look at the Parts Inside the Tape Well - Heads

The headsheads are what erases, records, and reads (plays) the tape. These are the most critical part of any tape player andthey cannot be repaired, only replaced on cassette decks. On reel to reel machines they can sometimes be resurfaced(lapped) but not so on cassette decks. Once wore out, they must be replaced or the machine is junk.

Cassette decks can have 1,2,3 or even 4 heads. Lets cover the most common which are the 1 and 2 head machines.

On a 1 head1 head machine, you only have the ability to play tapes. You cannot record. Think Walkman (portable) units, kidsplayers, and boomboxes that have one well for play and one well for play/record. Pic 1 is the tape well in a portable. Thehead is the silver thing in the middle. It's what reads the tape.

In pics 2-5 you see inside the well of a standard, non auto reverse, 2 head2 head machine. The head in the center is now aplay/record head. It does double duty. This is by far the most common setup.

In pic 2 you see a good shot of the layout of a 2 head machine. From left to right, erase head, play/record head, andcapstan/pinch roller. The erase head does just as the name implies, it erases the tape and gets it ready to be recorded on.On really cheap machines, they replace that part with a tiny permanent magnet on a swing arm. That setup is bottom ofthe barrel and only found on very low end machines. You want a machine with a proper erase head.

Pics 3-4 show you two focused close ups. pic 3 is the erase head, pic 4 is the play/record head.


Pic 6 shows you an autoreverse 2 headautoreverse 2 head setup. The erase and play/record head are sandwiched and rotate togetherdepending which way the tape is playing.

So what about these 3 and 4 head3 and 4 head machines I mentioned? A 3 head machine has an erase, record, and play head. Top ofthe line machines are setup this way. In an ideal world, the head used for recording is engineered di erently than oneused for playing. To extract the absolute best out of a tape, 3 or 4 head machines are the way to go. These machines arealso capable of letting you hear your recording as it's being made so you can do some test recordings and tweak on the

y.

What's a 4 head machine? Its a three head in an auto reverse setup. The record and play heads are sandwiched togetherin the center and rotate, on either side you have a very thin erase head that energized as needed. These machines arerare. Standard 3 head is the way to go.

In pic 5 you see a real clean shot of the inside of a 2 head well. Notice the top of the record/play head. See the re ectionon it? Notice the re ection clues you into the fact that surface is perfectly even, no dips or gouges. That's what you wantwhen buying a used deck regardless of head count. The roller is also perfect with no cracks. The capstan shaft has a weirdre ection from the light I used so ignore that.

Playing a tape is basically rubbing a rust coated plastic strip across a tiny electromagnet coil. Since there is friction, thehead wears over time. Cheap or really old (dull looking) tapes make it worse. The wear is never even. As the head wears,the contact pattern of the tape on the head becomes uneven. This causes high frequencies to su er. In really worn outmachines, even good tapes can sound like someone threw a towel over the speakers.

In pic 7 you see the door taken o a home deck. A great many home machines have removeable doors. You gently lift upand towards you and it pops o . Not all have this but most all mid to high end decks do. This makes it easier to get inthere and clean things.

In pic 8 you see an oddball. There were some decks made that the tape went at into a slide out drawer. Some of thosemachines had a little access door up top you pop open and can access the heads and pinch roller for cleaning. The onesthat don't have that may require removing the top cover for proper cleaning. There are head cleaning tapes but nothingbeats a proper cleaning.

What to clean the heads with? Proper way is Q-tips and head cleaning uid (pic 9). Like I mentioned before, I've beenusing pharmacy rubbing alcohol for decades and NEVER had an issue.


Step 6: Connecting to a Home Deck to Make a Recording

I see this question pop up lot on forums quite a bit.. "How do I connect my ipod/phone/pc to my deck so I can"How do I connect my ipod/phone/pc to my deck so I canrecord?" record?" Ok, here goes!

On the back of all component (stand alone) type tape decks you will nd IN and OUT jacks. These may be labelled PLAY(out) and RECORD (in). In the USA it's common to see RCA jacks as in pic 1. In Europe you may see DIN style connectorsthat perform the same task. On some but not all decks you may see MIC inputs for left and right as shown in pic 2.

You will be using the line level in, the jacks on the back marked IN, INPUT, or RECORD. Same function, three di erentways to name it. What can you connect there? Your ipod, phone, PC, a cd player, or any other LINE LEVEL source. In orderto connect an ipod, PC, or phone, you will need a cable that plugs into your player and has a pair of RCA plugs on theother end. Typically it's a red and white one. Red is for the right if you care to keep the music exactly as it was meant to beheard as far as where the musicians/instruments are in the sound eld.

The MIC jacks are for microphones and will sound horrible if you try to feed a music player into there. It overloads themand you'll get distortion.

Once you have the right cable, pick the loudest song you'll be recording and we'll setup for that.

Power up the deck, pop in a blank tape, hit record. Some decks require you hit play and record together. Once the tape ismoving, turn the record level adjustment up halfway. Some decks have a single control for level, some have separateknobs, some have two knobs that turn together. You want both left and right meters roughly the same. Next, hit play onyour source of music and slowly bring it's volume up till you see the meters just barely peaking past the zero mark. Allsetup, stop the tape, don't touch any levels, rewind the tape, get your playlist cued up on your player, hit record and playon as needed on the deck to get it going with record indicator on, count to 5, hit play on your source. The meters shouldstart moving and you're making a tape!

You now have the basics and are laying down your rst tape!

Now to answer a bunch of questions..

1) Why count to 5?Why count to 5? All blank tapes intended for music have a leader, a piece of clear tape at the beginning and end. Thisleader is 5 seconds long and you can't record on it.

2) My deck has no record level control or meters, what do I do?My deck has no record level control or meters, what do I do? Trial and error unfortunately. Make a test recordingstarting with volume on player at max and drop down in increments keeping track of how much you dropped each time.Play back the tape you made and see what produced the best sound. Continue using that setting until you get a betterrecorder with record level adjustment.

3) What's the di erence between old style needle in pic 2 (analog) meters and decks with digital meters like picWhat's the di erence between old style needle in pic 2 (analog) meters and decks with digital meters like pic3? 3? Functionally the same. They still have the same scale. Analog meters are slightly slower to show fast peaks.

4) My deck is a 3 head and has a tape monitor switch.My deck is a 3 head and has a tape monitor switch. 3 and 4 head decks allow you to listen to a recording as itsbeing made. You may hear a slight echo in the background when monitoring the recording that was just made.

5) Can I record louder?Can I record louder? Yes, by all means but di erent brands and formulations will react di erently to louder levels.Some can take +3 or +6 without issue. To keep it safe and assure you success until you learn your machine/tapelimitations, stay under the +3. What happens if it's too loud? Fuzzy distortion.


Step 7: Advanced Recording

Here's some advanced recording info to help you as you delve further into cassette.

Dolby noise reductionDolby noise reduction - Dolby reduces the hiss that's inherent to all tape recordings. If hiss doesn't bother you, don'tbother using it. If hiss is an issue, here's the breakdown of the di erent Dolby technologies found throughout the historyof cassette decks. They all basically compress the signal on record and then expand it back on playback in e ect,lowering the noise oor.

Dolby BDolby B - The oldest form of noise reduction. Dolby B tapes can be played back on any machine with or without Dolby.The e ect of playing back a Dolby B encoded tape on a player without it will seem like boosted highs. This is sometimeswelcomed by tapers making tapes to use on portables and such that don't have the performance of a fullsize home deck.

Dolby CDolby C - This format works on both highs and mids. Tapes recorded with C sound pretty awful on machines that can'tdecode it. The mids will be weird.

Dolby SDolby S - This was cassette tapes last hurrah. Superior to all other Dolby formats for cassette but not may machines hadit. By this time recordable CD was a ordable.

Dolby HX ProDolby HX Pro - This is a record only process compatible with all machines. It varies the bias (beyond the scope of thisinstructable) allowing for hotter audio peaks without distortion. If you listen closely, an attentive listener may pickup onthe fact it sacri ces lows in order to keep highs from distorting on peaks. Think of it as a parachute to keep you from


wrecking a recording if there's some loud passages you didn't account for when you set levels. You want a deck with thisfeature. Pic 1 shows a deck that has a similar but non-Dolby feature called Dynamics Detection.

Dolby look-a-likesDolby look-a-likes - There were some noise reduction systems out there that worked similar to Dolby. JVC for examplepushed ANRS and Super ANRS for a while. It didn't catch on and even they gave up and added Dolby to their decks.

Decks with Auto Calibration Decks with Auto Calibration pic 2 - This is another great feature to have, like HX Pro. You'll need to nd the manual toyour machine if it has it so you can read how it works on your particular machine. What this does is it puts the machineinto an automatic mode that records a series of tones at di erent settings on the tape. It then rewinds and plays back thetones listening to them to nd the best setting for your particular blank tape. Once complete, the machine rewinds and isready to record having calibrated its internal settings as best it can to match the chemistry of your tape. You still setrecord levels and everything else operates as normal. The process is only good till you power the machine o or eject thetape. It clears out the settings once that happens. Since all manufacture's tapes are slightly di erent, this process helpsyou squeeze the most performance from the tape. Some machines have a feature like this but it's manual and uses anindicator on the display you line up. This is not a common feature.

Bias settingsBias settings - Generally speaking, decks from the silver face era and older will require you to set some controls on thefront of the machine marked "bias" to the correct setting. Your blank tape should be marked normal, high bias, or metal.Set the switches accordingly for proper sounding recordings. By the time everybody quit making silver faced gear and itwas all black, those machines had auto sensing switches that detected the bias notches on the tape and set themselves.There are exceptions to this of course. If you see switches for bias and they say 120uS or 70uS, they need to be setaccording to what tape you use. Setting it wrong won't break anything, you'll just get a lousy recording.

Tech bonusTech bonus - On older machines, pretty much all machines from the top loader and the silver face era, there will be amechanical switch that switches internal circuits from record to play. Got a machine with a dead channel or one thatgoes bonkers pegging the meters and buzzing when put into record no matter what you do? Try cleaning the internalrecord / play switch. In pic 3 you see the inside of an older drawer style deck from the silver face era. In the center bottomof the pic are two silver vertical assemblies that are long. Those are the record / Play switches. Pop a recordable tape inthe machine (you're not going to record on it and machine should be unplugged) Bathe them in electrical contactcleaner (available at auto parts stores) while mashing the record button, hitting stop, hitting record, hitting stop. You'relooking to actuate that switch, repeatedly. You'll see one of the ends have a plastic piece that moves maybe 1/4" or sowhen actuated. Not all machines have two, some have one. This feature was replaced by chips towards the late 1980's so"newer" machines don't have these.

Got scratchy controls or controls that act up? Same drill, bathe the circuit board side of the switch or control with contactcleaner, cycle the switches or turn the knobs back and forth. They should clear up. These are common problems with oldaudio gear. Too many stereos get tossed to the curb just because of noisy controls.

Do this outdoors. The fumes from this stu is strong. Don't forget to let the contact cleaner dry out thoroughly beforeplugging gear in.


Step 8: Beware! - Collecting Decks Gets Addicting

There's three of mine of repaired. New belts, thorough tape path cleaning and they sing once again. I hope thisinstructable helped you get an old machine up and running again. Don't be afraid to dig in and try. People that canperform even basic cassette deck repairs are getting hard to come by. Not every deck has succumbed to a major failure.You'd be surprised how many come back to life with these simple tips I posted here.

If you want to learn more about the tapes themselves please check out my Cassette Tape 1101 instructable. More thanyou'd ever want to know about cassette tapes.


My experience using cassette tapes to record lectures way back when:C60 Great, very reliable. C90 Like the extra space, reliable. C120 Sounds like a good idea, jamtastic mess after a few plays.

You've got it spot on. C120 or longer is a BAD idea.

I have about 4 of these still around both portable and home stereo decks record and play. Havenot used them in awhile I also have a lot of the cassette. I even have a couple of the 8 trackmachines and tapes. I did not see anything about repairing the broken tapes at which I did fix myown both the cassette and 8track back in the day

I have an instructable on fixing cassette tapes. Take a look on my projects.

You really need one of these to repair any cassette deck. I was the head tech at Opus One inPgh in the late 70's early 80's. We were the warranty station for many of the mfg's like Sony,Kennwood, and high priced things like Tandberg. The problem with most single motor and dualmotor (reel and capstan) cassette decks is a loss of reel torque. Even three motor decks likeNakamichi can exhibit poor back tension on the supply reel, which can cause playback issues likeskew; poor torque on the take up will usually eat tapes. Single motor and dual motor units use feltclutches that wear out.

You will then need an alignment tape. You use this to first align the playback response as well asthings like transport speed - typically a 3.15kHz tone for wow, flutter, and speed check. You thenalign the record electronics which kinda sucks to do on two head machines... on things like open


reel and three head Nak's it's the same but you can playback the recording as you go, since theplayhead is located after the record head.

So you really need one of these torque meters - see photo. A pic of my lab also attached. I fixedlots of gear - both pro and consumer.

ajawamnet - google it.

This was meant for the tinkerer trying to keep old gear running or fixing on a budget.

That is some good Informationen. Where do you get a torquemeter? Are they still in Produktion orfor sale?

I still have my cassette surgical kit, assembled/bought in e. '70's. I love my collection, much tapedoff radio broadcasts and so easy to create custom tapes. Thanks for the memories! [One,however, just froze and too bad (live Robert Gordon with Chris Spedding)] ..

A froze tape can sometimes be freed up by slapping it hard against the palm of your hands a fewtimes, flip it, repeat, put in machine and try a few cycles of FFWD/REW.

This is great.. thanks! The issue i'm having is my deck is struggling to play some tapes. The feedis inconsistent and sometimes stops altogether. It acts like it's having trouble turning the tape, buti can spin it manually just fine. Any idea if this kind of maintenance on the deck will help, or do ijust have some old, bum tapes?

Thanks for putting this all together. Lot's of great information! I've got a bunch of old portable tapeplayers and recorders, all of which have stopped turning. I assumed it was bad belts etc. butnever had the time to troubleshoot and attempt repairs. This may give me the motivation I need!

This is bloody brilliant! I grew up with these, along with 8-track and still have both players. Idefinitely need to do some cleaning to both. Thanks!

I had a Panasonic 8-track player and the best thing about it was the Pana-ject feature where itwould automatically eject the cartridge at the end of the fourth track. You always new that thenext time you would play, you would be at the beginning of the track.

Handy for recording phone calls automatically on a landline . The landline uses about 60 volts onits line when the phone is on the hook. When the receiver is lifted the voltage drops to 6 to 10volts or so . So tap off from the blue and white and put a 48volt zenner in the line and a digitalchip that inverts the signal with its own battery power supply . When voltage drops to zero thechip puts voltage out so feed that to the remote control switch of the tape recorder

POTS (Plain Old Telephone Systems) use 48 VDC (positive ground to reduce galvanicdeterioration) that comes from the 70 VDC roundcells located at the CO (Central Office) or fromsome other thing like your ONT that they connect to the old NID box. The reason for 48 is thatanything under 50V can be class II and will be under the UL cert (it's required at >50V). POTSthings like modems and anything that is connected have to be able to withstand FCC part 68which is very specific as to withstand voltages from things like lightening strikes and voltagesurges. The DAA interface has specific test procedures such as drop tests and common modebreakdown. I designed lot of modems for things like early IoT things (my patent 6208266 ) andother telemetry device that interfaced to crap like that way back when.

ajawamnet


Lots of good advice about these old machines. I have numerous cassette tapes that I would liketo convert to digital, but despite having several tape recorders, all but one mono player haveweak belts so the take up spindle doesn't have enough horsepower to pull the tape through andkeep it from jamming up in there.

That's more likely the felt clutches if it's a single motor (typical) consumer cassette deck. See mypost above.

ajawamnet

This is spooky! Yesterday I rescued a 80s Sony combo and tried to play tapes but the sound wasdull and today I was going to check the internet for a way to clean the heads and got thisinstructable at my mail!!! Spooky as halloween!

HiI got the same Pioneer CT 3000 that you show on some of the pictures. Unfortunately thetransport doesnt work. There are still the first belts in it. Over here in Germany i wasnt able tofind a set of replacement belts. Do you have a good source for a set for this deck? Seems to be abit more complicated than other decks, but is a fantastic system. Would be happy about anyinformation. Thanks. RegardsWerner

Thanks for this. I just got an old '70s, tall-spindle record player/radio/cassette player, and theplayer only plays on one channel. I know what needs done, but the disassembly part of theequation was a bit iffy for me, and I spent 20 years working in electronics--a LONG time ago.Never knew what to do about the black goo though. Thanks again.

A fantastic resource - thank you! I've added a link to this from the Restarters Wiki -https://wiki.restarters.net/Audio_equipment

(If you care to, take a look at the Restarters Wiki. Our mission is to fix our relationship withelectronics by promoting repair. If you felt like joining the community we'd welcome you with openarms, and if you felt able to add to the wiki that would be incredible. You can register atrestarters.net. People who can both fix things and write good copy (as you can) are unfortunatelyfew and far between.)

This is fantastic! Lots of great info here :)


https://wiki.restarters.net/Audio_equipment

http://restarters.net

intro to cassette recorder operation, maintenance, and repair

Documents